getting tired of these spam calls

I didn't pick up the phone and it called me twice.

Spam

Caller: (02) 9137 2389

I had a missed call from this number
I called them back and it went straight to an answering machine
A male robot voicemail
"Hi, all of our operators are busy right now, we will return your call shortly"

Caller: 91372389 - unknown

I answered because I was expecting another call and I said hello but no one responded

Caller: ‭(02) 9137 2389‬

No one said hello

Caller: Rubbish

Some cold call about Government retirement ,absolutely rubbish

I called back the number (02) 9137 2389 and reached vm that did not mention the company name

I Rang back and got RVA that all the operators were busy. Must be T.M.

Answered the call because I was expecting a call from medical centre. Hung up when I answered. Another nuisance call

I rang once and got disconnected